i once managed the product that calculated the cost basis for your property tax bill in most US counties & states (and some international jurisdictions), and it was common knowledge there that home prices were disconnected from construction costs. construction cost relative to home prices is interesting to a company like buildzoom because they're in the construction business (and finding the coming construction booms…
Don't mean to boil down your entire well-written post to a single point, but I maintain that Georgism is the only sensible solution to this problem.